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Feature: Add Vigenere Cipher Encode & Decode

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- Added Vigenere Encode & Decode
- Added metadata for /config/ relating to this additon
This commit is contained in:
Matt C 2016-12-03 20:54:28 +00:00
parent 20d9903572
commit 560712cee3
3 changed files with 128 additions and 1 deletions
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97
src/js/operations/Cipher.js
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@ -3,7 +3,7 @@
/**
* Cipher operations.
*
* @author n1474335 [n1474335@gmail.com]
* @author n1474335 [n1474335@gmail.com] & Matt C [matt@artemisbot.pw]
* @copyright Crown Copyright 2016
* @license Apache-2.0
*
@ -385,6 +385,101 @@ var Cipher = {
return encrypted.ciphertext.toString(Utils.format[args[2]]);
},
/**
* @constant
* @default
*/
VIG_ENC_KEY: "cipher",
/**
* Vigenere cipher encode.
*
* @param {string} input
* @param {Object[]} args
* @returns {string}
*/
run_vigenc: function (input, args) {
var alphabet = "abcdefghijklmnopqrstuvwxyz",
keyword = args[0].toLowerCase(),
output = "",
fail = 0,
keyIndex,
msgIndex,
chr;
if (keyword) {
if (/^[a-zA-Z]+$/.test(keyword)) {
for (var i = 0; i < input.length; i++) {
if (alphabet.indexOf(input[i]) >= 0) {
chr = keyword[(i - fail) % keyword.length]; //Gets the corresponding character of keyword for current letter, accounting for chars not in alphabet
keyIndex = alphabet.indexOf(chr); //Gets location in vigenere square of keyword char
msgIndex = alphabet.indexOf(input[i]); //Gets location in vigenere square of message char
output += alphabet[(keyIndex + msgIndex) % 26]; //Gets encoded letter by finding sum of indexes modulo 26 and finding the letter corresponding to that
} else if (alphabet.indexOf(input[i].toLowerCase()) >= 0) {
chr = keyword[(i - fail) % keyword.length].toLowerCase();
keyIndex = alphabet.indexOf(chr);
msgIndex = alphabet.indexOf(input[i].toLowerCase());
output += alphabet[(keyIndex + msgIndex) % 26].toUpperCase();
} else {
output += input[i];
fail++
}
}
} else {
throw "Keyword can only consist of letters.";
}
} else {
throw "A keyword is required.";
}
return output;
},
/**
* @constant
* @default
*/
VIG_DEC_KEY: "cipher",
/**
* Vigenere cipher decode.
*
* @param {string} input
* @param {Object[]} args
* @returns {string}
*/
run_vigdec: function (input, args) {
var alphabet = "abcdefghijklmnopqrstuvwxyz",
keyword = args[0].toLowerCase(),
output = "",
fail = 0,
keyIndex,
msgIndex,
chr;
if (keyword) {
if (/^[a-zA-Z]+$/.test(keyword)) {
for (var i = 0; i < input.length; i++) {
if (alphabet.indexOf(input[i]) >= 0) {
chr = keyword[(i - fail) % keyword.length];
keyIndex = alphabet.indexOf(chr);
msgIndex = alphabet.indexOf(input[i]);
output += alphabet[(msgIndex - keyIndex + alphabet.length ) % 26]; //subtract indexes from each other, add 26 just in case the value is negative, modulo to remove if neccessary
} else if (alphabet.indexOf(input[i].toLowerCase()) >= 0) {
chr = keyword[(i - fail) % keyword.length].toLowerCase();
keyIndex = alphabet.indexOf(chr);
msgIndex = alphabet.indexOf(input[i].toLowerCase());
output += alphabet[(msgIndex + alphabet.length - keyIndex) % 26].toUpperCase();
} else {
output += input[i];
fail++
}
}
} else {
throw "Keyword can only consist of letters.";
}
} else {
throw "A keyword is required.";
}
return output;
}
};